{
    "mode": "man",
    "parameter": "uuidd",
    "section": "8",
    "url": "https://www.chedong.com/phpMan.php/man/uuidd/8/json",
    "generated": "2026-06-14T01:13:43Z",
    "synopsis": "uuidd [options]",
    "sections": {
        "NAME": {
            "content": "uuidd - UUID generation daemon\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "uuidd [options]\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "The uuidd daemon is used by the UUID library to generate universally unique identifiers\n(UUIDs), especially time-based UUIDs, in a secure and guaranteed-unique fashion, even in the\nface of large numbers of threads running on different CPUs trying to grab UUIDs.\n",
            "subsections": []
        },
        "OPTIONS": {
            "content": "",
            "subsections": [
                {
                    "name": "-d --debug",
                    "content": "Run uuidd in debugging mode. This prevents uuidd from running as a daemon.\n",
                    "flag": "-d",
                    "long": "--debug"
                },
                {
                    "name": "-F --no-fork",
                    "content": "Do not daemonize using a double-fork.\n",
                    "flag": "-F",
                    "long": "--no-fork"
                },
                {
                    "name": "-k --kill",
                    "content": "If currently a uuidd daemon is running, kill it.\n",
                    "flag": "-k",
                    "long": "--kill"
                },
                {
                    "name": "-n --uuids",
                    "content": "When issuing a test request to a running uuidd, request a bulk response of number UUIDs.\n",
                    "flag": "-n",
                    "long": "--uuids"
                },
                {
                    "name": "-P --no-pid",
                    "content": "Do not create a pid file.\n",
                    "flag": "-P",
                    "long": "--no-pid"
                },
                {
                    "name": "-p --pid",
                    "content": "Specify the pathname where the pid file should be written. By default, the pid file is\nwritten to {runstatedir}/uuidd/uuidd.pid.\n",
                    "flag": "-p",
                    "long": "--pid"
                },
                {
                    "name": "-q --quiet",
                    "content": "Suppress some failure messages.\n",
                    "flag": "-q",
                    "long": "--quiet"
                },
                {
                    "name": "-r --random",
                    "content": "Test uuidd by trying to connect to a running uuidd daemon and request it to return a\nrandom-based UUID.\n",
                    "flag": "-r",
                    "long": "--random"
                },
                {
                    "name": "-S --socket-activation",
                    "content": "Do not create a socket but instead expect it to be provided by the calling process. This\nimplies --no-fork and --no-pid. This option is intended to be used only with systemd(1).\nIt needs to be enabled with a configure option.\n",
                    "flag": "-S",
                    "long": "--socket-activation"
                },
                {
                    "name": "-s --socket",
                    "content": "Make uuidd use this pathname for the unix-domain socket. By default, the pathname used is\n{runstatedir}/uuidd/request. This option is primarily for debugging purposes, since the\npathname is hard-coded in the libuuid library.\n",
                    "flag": "-s",
                    "long": "--socket"
                },
                {
                    "name": "-T --timeout",
                    "content": "Make uuidd exit after number seconds of inactivity.\n",
                    "flag": "-T",
                    "long": "--timeout"
                },
                {
                    "name": "-t --time",
                    "content": "Test uuidd by trying to connect to a running uuidd daemon and request it to return a\ntime-based UUID.\n",
                    "flag": "-t",
                    "long": "--time"
                },
                {
                    "name": "-V --version",
                    "content": "Output version information and exit.\n",
                    "flag": "-V",
                    "long": "--version"
                },
                {
                    "name": "-h --help",
                    "content": "Display help screen and exit.\n",
                    "flag": "-h",
                    "long": "--help"
                }
            ]
        },
        "EXAMPLE": {
            "content": "Start up a daemon, print 42 random keys, and then stop the daemon:\n\nuuidd -p /tmp/uuidd.pid -s /tmp/uuidd.socket\nuuidd -d -r -n 42 -s /tmp/uuidd.socket\nuuidd -d -k -s /tmp/uuidd.socket\n",
            "subsections": []
        },
        "AUTHOR": {
            "content": "The uuidd daemon was written by Theodore Ts’o <tytso@mit.edu>.\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "uuid(3), uuidgen(1)\n",
            "subsections": []
        },
        "REPORTING BUGS": {
            "content": "For bug reports, use the issue tracker at https://github.com/karelzak/util-linux/issues.\n",
            "subsections": []
        },
        "AVAILABILITY": {
            "content": "The uuidd command is part of the util-linux package which can be downloaded from Linux Kernel\nArchive <https://www.kernel.org/pub/linux/utils/util-linux/>.\n\n\n\nutil-linux 2.37.2                            2021-06-02                                     UUIDD(8)",
            "subsections": []
        }
    },
    "summary": "uuidd - UUID generation daemon",
    "flags": [
        {
            "flag": "-d",
            "long": "--debug",
            "arg": null,
            "description": "Run uuidd in debugging mode. This prevents uuidd from running as a daemon."
        },
        {
            "flag": "-F",
            "long": "--no-fork",
            "arg": null,
            "description": "Do not daemonize using a double-fork."
        },
        {
            "flag": "-k",
            "long": "--kill",
            "arg": null,
            "description": "If currently a uuidd daemon is running, kill it."
        },
        {
            "flag": "-n",
            "long": "--uuids",
            "arg": null,
            "description": "When issuing a test request to a running uuidd, request a bulk response of number UUIDs."
        },
        {
            "flag": "-P",
            "long": "--no-pid",
            "arg": null,
            "description": "Do not create a pid file."
        },
        {
            "flag": "-p",
            "long": "--pid",
            "arg": null,
            "description": "Specify the pathname where the pid file should be written. By default, the pid file is written to {runstatedir}/uuidd/uuidd.pid."
        },
        {
            "flag": "-q",
            "long": "--quiet",
            "arg": null,
            "description": "Suppress some failure messages."
        },
        {
            "flag": "-r",
            "long": "--random",
            "arg": null,
            "description": "Test uuidd by trying to connect to a running uuidd daemon and request it to return a random-based UUID."
        },
        {
            "flag": "-S",
            "long": "--socket-activation",
            "arg": null,
            "description": "Do not create a socket but instead expect it to be provided by the calling process. This implies --no-fork and --no-pid. This option is intended to be used only with systemd(1). It needs to be enabled with a configure option."
        },
        {
            "flag": "-s",
            "long": "--socket",
            "arg": null,
            "description": "Make uuidd use this pathname for the unix-domain socket. By default, the pathname used is {runstatedir}/uuidd/request. This option is primarily for debugging purposes, since the pathname is hard-coded in the libuuid library."
        },
        {
            "flag": "-T",
            "long": "--timeout",
            "arg": null,
            "description": "Make uuidd exit after number seconds of inactivity."
        },
        {
            "flag": "-t",
            "long": "--time",
            "arg": null,
            "description": "Test uuidd by trying to connect to a running uuidd daemon and request it to return a time-based UUID."
        },
        {
            "flag": "-V",
            "long": "--version",
            "arg": null,
            "description": "Output version information and exit."
        },
        {
            "flag": "-h",
            "long": "--help",
            "arg": null,
            "description": "Display help screen and exit."
        }
    ],
    "examples": [
        "Start up a daemon, print 42 random keys, and then stop the daemon:",
        "uuidd -p /tmp/uuidd.pid -s /tmp/uuidd.socket",
        "uuidd -d -r -n 42 -s /tmp/uuidd.socket",
        "uuidd -d -k -s /tmp/uuidd.socket"
    ],
    "see_also": [
        {
            "name": "uuid",
            "section": "3",
            "url": "https://www.chedong.com/phpMan.php/man/uuid/3/json"
        },
        {
            "name": "uuidgen",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/uuidgen/1/json"
        }
    ]
}